The proposed research will systematically analyze the normal organization of frontal lobe motor fields in macaque monkeys by combining and correlating anatomical and physiological approaches in the same individuals. Although similar multitechnical paradigms have been very successful in defining the organization of other cortical systems, they have not yet been systematically applied to the study of primate coritcal motor fields. The specific aims will address aspects of the extrinsic and intrinsic organization of primary motor, premotor, and supplementary motor cortical regions via four types of experiments. First, the locations, architectonics and extrinsic connections of each field will be determined by correlating data from intracortical microstimulation (ICMS), histochemical staining (showing cytoarchitecture as well as the differential distributions of certain enzyme systems and myelin), and connectional methods (transport of anatomical tracers) in the same animal. Second, the internal motor topography and its relationship to local architectonic features in each field will be examined by correlating ICMS data with histochemical data. Third, for each field, the internal topographic relationships between somatosensory inputs, motor outputs, and local architectonic features will be determined by correlating data from multiunit recording of neural responses to somatosensory stimulation, ICMS and histochemical staining in the same animal. Fourth, for each field, the pattern of internal connections will be correlated to motor or sensory topography and architecotnic features in the same animal. The results of this research program will advance our understanding of the functional and connectional relationships between and within frontal lobe motor fields in primates.